On Lyft's conference call Tuesday evening, management was optimistic about the competitive landscape, which was a positive indicator about eventual profitability, according to Asad Hussain, an emerging technology analyst at PitchBook.

"However, Lyft withdrew providing gross bookings data, which complicates the ability of investors to understand pricing trends," Hussain said in an email.

While the market doesn't typically appreciate those kinds of "data pull-backs," Hussain said, he wouldn't be surprised if Uber were to make a similar move when the time comes for its own quarterly reports.

Judging by the market's severe reaction, Thursday's report did little to quell the investment community's long-term concerns about Lyft's growth prospects. Shares have fallen 23% from where they priced in late March.

Lyft offered encouraging results in its report, but still has "a lot to prove," Guggenheim analyst Jake Fuller said in a note to clients Wednesday morning. Fuller, who has a "neutral" rating on Lyft, said the report was light on details.

"Limited detail from LYFT around core metrics like number of rides, bookings and take-rate make it more difficult to decipher trends in unit economics and competitive dynamics," he wrote.

In a bright spot, management announced a new partnership with Waymo, which PitchBook's Hussain sees as a win for Lyft given the "long-term existential threat posed by autonomous vehicles."

The report comes ahead of Uber's expected public market debut later this week. Lyft's much-larger competitor is expected to price its initial public offering Thursday and begin trading Friday. Analysts have long cited Uber as a major threat to Lyft.

At an expected market value of between $80 billion and $86 billion — Uber would be the third-largest US-listed IPO on record, according to Dealogic. Only Alibaba and Facebook's debuts were larger.